RISON Decode

RISON decoding is broken. Found the below reference on the initial commit.

Well, almost. RISON Decode operation is broken. The "decode option" dropdown contains 3 `undefined` options, and makes it unusable. Replacing l.31 `type: "editableOption",` with `type: "option",` should do the trick.

Thanks tho.

_Originally posted by @baphael in https://github.com/gchq/CyberChef/issues/1023#issuecomment-2072603935_

Start by locating the RISON Decode operation and inspect the line 31 configuration referenced in the issue. Confirm the decode option dropdown currently renders three undefined entries, then verify that the dropdown presents usable named options after the change.

Written by the indexing model from the issue text.